Metallgesellschaft Aktiengesellschaft

Eilhard Hillrichs

Ulrich Heinrich Sander

Nikola Anastasijevic

Gert Ungar

Karl Lohrberg

Hans-Martin Stonner

Johann Schlauer

Volker Brucken

Manfred Kienberger

Ernst Stoldt

Process of preparing solutions of alkali peroxide and percarbonate

Process of preparing alkali peroxide solutions

The ammonium polysulfide is produced in at least one electrochemical cell, to which an aqueous ammonium sulfide solution is supplied as electrolyte. The cell comprises an anode, a gas diffusion cathode, and between the anode and the cathode an electrolyte chamber, where the cell voltage is 0.01 to 5V. The cathode has an electrically conductive, gas-permeable carbon layer, over which flows gas containing free oxygen, and which is in contact with the electrolyte. O.sub.2 -containing gas is introduced into the electrolyte chamber, thereby forming hydroperoxide anions (OOH.sup.-) in the electrolyte chamber. From the electrolyte chamber a solution containing ammonium polysulfide and a residual gas are withdrawn.

Process for the electrochemical production of ammonium polysulfide

An aqueous solution which contains ammonium polysulfide is proportionally added to the sour water, which contains cyanide ions, ammonium ions, and sulfide ions. At least part of the cyanide ions contained in the sour water is converted to thiocyanate ions by the ammonium polysulfide. The solution which contains ammonium polysulfide is prepared from an aqueous solution by oxidation in an electrochemical cell. That aqueous solution may consist entirely or in part of sour water.

Process for decreasing the corrosiveness of a sour water

The membrane serves to cover a gas diffusion electrode on its outside surface facing a liquid electrolyte. The membrane is impermeable to gas and water-absorbent. It comprises a textile carrier layer. At least one gas-sealing layer, which contains ion exchange material and binder in a weight ratio from 10:1 to 1:2, is bonded to the textile carrier layer. In the manufacture of the membrane, an adhesive layer consisting of a binder in a solvent and subsequently at least one gas-sealing layer are applied to the textile carrier layer.

Membrane for a gas diffusion electrode, process of manufacturing the

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Budingen, Germany

Eilhard Hillrichs